This was rumored three times in playboy magazine. First in September 1967, then December 1967, and again in May 1971. It was to be published in 1972 by Doubleday and told tales of Shep's army days.
He mentioned the book at his appearance at Newark College of Engineering in 1968.
3-28-70 Overseas Press Club Conference
Q "When does T.S. Mac come out?"
A "The title has been changed and it will be out this fall."
4-15-70 WRUC FM interview
Next book coming out late in the fall, around November. It is not "T.S. Mac". It has been retitled. Many of the stories have appeared in Playboy.
12-19-1976 New York Times review of "Phontom of the Open Hearth" - "His latest novel, "The Secret Mission of the Blue Assed Buzzard,' about his Army career, is due in January."
Two probable chapters which first appeared in Playboy are:
Playboy Sept 1967 - "The Secret Mission of the Blue-Assed Buzzard"
Playboy May 1971 "The Unforgettable Exhibition Game of the Giants versus the Dodgers, Tropical Bush league"